DUBLIN (AP) — An international conference celebrating Roman Catholicism opened Sunday in Ireland against a backdrop of anger over child abuse cover-ups and evidence of declining faith in core church beliefs.

More than 20,000 Catholics, many from overseas, gathered for an open-air Mass in a Dublin stadium at the start of the Eucharistic Congress, a weeklong event organized by the Vatican every four years in a different part of the world. The global gathering, begun in the 19th century and last held in Quebec in 2008, highlights the Catholic Church's belief in transubstantiation, the idea that bread and wine transforms during Mass into the actual body and blood of Jesus Christ.

An opinion poll of Irish Catholics found that two-thirds of Irish Catholics don't believe this, nor do they attend Mass weekly. The survey, published last week in The Irish Times with an error margin of 3 points, also found that just 38 percent believe Ireland today would be in worse shape without its dominant church. And just three-fifths even knew the Eucharistic Congress was coming to Ireland.

Such views reflect rapid secularization and alienation with the church in Ireland, where church and state once were tightly intertwined. The last time Ireland hosted the Eucharistic Congress in 1932, more than 1 million — a quarter of Ireland's population — packed Dublin's Phoenix Park for Mass with nary a dissenting voice...